1. Field of the Invention
This invention relates generally to food product compositions, and more particularly to confectionery products, especially chocolate and chocolate-type products containing a nutritive carbohydrate sweetener, a fat or reduced calorie fat or combination thereof, and an edible emulsifier or surfactant, wherein the fat content is 20-24.5% by weight. In addition to the lowfat content, the food products of the present invention have rheology characteristics which are fully acceptable for moulding, enrobing and extruding operations. The present invention also relates generally to a process for producing a lowfat chocolate and more specifically, to the process of preparing and formulating said product compositions, e.g., confectionery products, especially chocolate and chocolate-type products having fat or reduced calorie fat content or combination thereof, in which the total fat or reduced calorie fat content can be as low as 20%.
2. Description of the Prior Art
Food products made from ingredients including d carbohydrate sweetener such as sucrose and an edible oil or fat such as cocoa butter are well known. An important group of these food products is comprised of confections, including candy.
The most popular chocolate or chocolate candy consumed in the United States is in the form of sweet chocolate or milk chocolate. Milk chocolate is a confection which contains nonfat milk solids, milkfat, chocolate liquor, a nutritive carbohydrate sweetener, cocoa butter and may include other optional ingredients such as emulsifiers and flavorings and other additives. Sweet chocolate differs from milk chocolate in that it requires more chocolate liquor and limits the amount of milk solids. Semisweet chocolate requires at least 35% by weight chocolate liquor and is otherwise similar in definition to sweet chocolate. Commonly known dark chocolate, generally containing only chocolate liquor, a nutritive carbohydrate sweetener and cocoa butter, is by definition either a sweet chocolate or a semisweet chocolate. Buttermilk chocolate and skim milk chocolate differ from milk chocolate in that the milk fat comes from various forms of sweet cream buttermilk and skim milk, respectively, and in the case of skim milk, the total amount of milkfat is limited to less than the minimum for milk chocolate. Mixed dairy product chocolates differ from milk chocolate in that the milk solid includes any or all of the milk solids listed for milk chocolate, buttermilk chocolate or skim milk chocolate. White chocolate differs from milk chocolate in that it contains no non-fat cocoa solids. As used herein, the term "chocolate" denotes chocolate, baking chocolate, milk chocolate, sweet chocolate, semisweet chocolate, buttermilk chocolate, skim milk chocolate, mixed dairy product chocolate, white chocolate and non-standardized chocolates, unless specifically identified otherwise.
Chocolate used in foods in the United States is subject to a standard of identity established by the U.S. Food and Drug Administration (FDA) under the Federal Food, Drug and Cosmetic Act. The U.S. definitions and standards for the various types of chocolate are well established. Nonstandardized chocolates are those chocolates which have compositions which fall outside the specified ranges of the standardized chocolates.
Examples of nonstandardized chocolates result when the cocoa butter or milkfat are replaced partially or completely; or when the nutritive carbohydrate sweetener is replaced partially or completely; or flavors imitating milk, butter or chocolate are added or other additions or deletions in formula are made outside the USFDA standards of identify of chocolate or combinations thereof.
As a confection, chocolate can take the form of solid pieces of chocolate, such as bars or novelty shapes, and can also be incorporated as a component of other, more complex confections where chocolate is combined with and generally coats other foods such as caramel, nougat, fruit pieces, nuts, wafers or the like. These foods are characterized as microbiologically shelf-stable at 65.degree.-85.degree. F. under normal atmospheric conditions. Other complex confections result from surrounding with chocolate soft inclusions such as cordial cherries or peanut butter. Other complex confections result from coating ice cream or other frozen or refrigerated desserts with chocolate. Generally chocolate used to coat or surround foods must be more fluid than chocolates used for plain chocolate solid bars or novelty shapes.
The process of coating chocolate onto a food is known as enrobing. Enrobing is accomplished when the chocolate is in a fluid state and a proper viscosity must be maintained in order to produce a satisfactory coated product.
Chocolate can also be moulded. By moulding, it is meant that chocolate, either plain or mixed with nuts, raisins, crisped rice and the like is deposited in moulds, allowed to cool and hardened into solid pieces and then removed from the mould. Chocolate moulded into plain chocolate pieces generally can be somewhat more viscous than coating chocolates since the chocolate can be vibrated into a mould over a longer period of time than allowed in enrobing. However, chocolate moulded with food inclusions generally must be as fluid as coating chocolates.
Some novelty shapes made of plain chocolate are extruded onto a cold belt such as Kisses.RTM. or chocolate chips. Because the chocolate is extruded onto a cold belt, it must be more viscous than for moulded plain chocolate. Extruded chocolates are essentially extruded to a particular shape and require a yield value to retain the extruded shape while the chocolate hardens.
As noted above, the rheological characteristics, i.e., the flow properties, of chocolate are very important. Chocolate is non-Newtonian in nature. That is, it flows differently depending upon how the chocolate is stirred or pumped or how quickly it is poured. These characteristics are described by two measurements: a yield value, which relates to how much force one must use to start the chocolate flowing; and a plastic viscosity, which approximates the work done to keep the chocolate flowing uniformly. If either the yield value or the plastic viscosity is not within certain prescribed limits, poor processing will result. J. Chevalley, J. Texture Studies, 6: 177-196 "Rheology of Chocolate" (1975) reported typical Casson yield values and Casson plastic viscosities for commercial coating chocolates of 0-200 dyn/cm.sup.2 and 5-25 poise, respectively, and for commercial moulding chocolates of 100-2000 dyn/cm.sup.2 and 10-200 poise, respectively. These values were confirmed some thirteen years later by J. Chevalley, Industrial Chocolate Manufacture and Use, Blackie & Son Ltd. Glasgow and London by AVI (1988).
The process of making chocolate is reviewed generally in B. L. Zoumas and E. J. Finnegan, "Chocolate and Cocoa", Kirk-Othmer Encyclopedia of Chemical Technology, Vol. 6 (3rd Ed., Wiley-Interscience, New York) 1-19 (1985). Processes for producing chocolate can be either "wet" or "dry". In the "wet" process, sweetened condensed milk is codried with chocolate liquor to generate a crumb that is microbiologically stable. In the "dry" process, milk powder is utilized rather than condensed milk. As such, the ingredients as received are microbiologically stable.
The "dry" process of making chocolate consists essentially of the steps of mixing, refining, conching or liquefying, standardizing and tempering to generate the desired rheology as needed for enrobing, moulding or producing novelty shapes.
In the first step in the preparation of milk chocolate, a nutritive carbohydrate sweetener such as extra fine grade granulated sucrose is combined and mixed with cocoa butter, chocolate liquor and spray dried whole milk powder. The resulting mixture is a paste. Next, in the refining step, essentially a fine grinding operation, the coarse paste from the mixer is passed between steel rollers and converted to a refined flake. Refining breaks up crystalline sugar, fibrous cocoa matter and milk solids such that the sizes of the particles are significantly reduced. This particle size reduction results in the desired smoothness of the chocolate. Fine chocolates usually have no particles larger than 20 or 25 microns. This is usually accomplished by passing the mixture through a plurality of refining rolls.
In the conching step, the mixture is then stirred while heating to give the final desired consistency to the milk chocolate. This mixing-kneading process allows moisture and volatile components to escape while smoothing the chocolate paste and is critical to the flavor and texture development of the chocolate.
Alternatively to the conching step, the liquefying step mixes refined flake under high shear over a short period of time. The refined flake is quickly converted to a suspension of solids in a continuous fat phase. The lack of flavor development can be corrected by pretreating the liquor and cocoa butter.
Additional fat and emulsifier are then added in the standardizing or finishing step to adjust viscosity to final specifications.
The final step in obtaining the desired rheology of the chocolate is tempering, a process of inducing satisfactory crystal nucleation of the liquid fat in the chocolate. If the chocolate is improperly cooled, the resulting chocolate will have a grainy texture as well as poor color and appearance.
Finished chocolate is a suspension of very fine particles (usually less than 50 microns) in fat. The particles usually consist of cocoa solids and crystalline sucrose as well as milk solids in the case of milk chocolate. The cocoa solids in the chocolate liquor and the milk solids have normally been processed so they are fine enough to be incorporated into a chocolate mixture. Sucrose, however, requires considerable size reduction since extra fine grade sucrose, for example, typically varies in crystal size from about 40 to 1000 microns. To satisfactorily function as an ingredient in chocolate, therefore, these sucrose crystals should be reduced in size to less than about 50 microns. Similar considerations apply in the processing of other types of confections. It is known that at least about 50% of the surface area of particles in milk chocolate is produced by the presence of particles below two microns in size. The presence of these ultrafine particles increases viscosity and increasing amounts of fat, e.g., cocoa butter, are required to coat such particles in order for the chocolate to flow properly in manufacturing operations.
Of particular concern in today's market is the fat content of a product. The amount of total fat in chocolates may vary somewhat depending on the formulation and process involved. In recent years, in view of this concern, there has been a steady reduction in the total fat contents of all chocolate. See B. Minifie, Chocolate, Cocoa, and Confectionery-Science and Technology, 3rd Edition, Van Nostrand Reinhold, New York (1989) p. 205. In fact, as Minifie reports, "good-quality finely ground chocolates with total fat contents down to 28% can now be produced and satisfactorily moulded. Lower quality chocolates with coarser particle size can be produced down to 25%. Particularly with milk chocolate, quality suffers with fat contents below 30%, the texture becoming pasty with a lack of snap."
L. R. Cook, Chocolate Production and Use, Books for Industry, Inc., New York (1975) p. 214, reports that in order to maintain the proper rheological properties, chocolate requires a minimum amount of total fat from 29 to 32% by weight. It was commonly believed by the skilled artisan that if the fat level was below said range, quality defects such as mealy, dry or powdery texture, and excessive coating permeability leading to dry centers would result. S. T. Beckett, PMCA Research Notes 16 (1):1-2 (April 1992) reported the production of cake chocolate with a fat content as low as 25% but acknowledged the same was extremely "thick".
It is thus well known in the art that the amount of fat present in chocolate will affect the flow properties of the chocolate, i.e., the addition of fat to a chocolate decreases both the yield value and the plastic viscosity. Consequently, fat content must therefore be varied according to the intended use. For example, proper fat content for moulding chocolate was reported at 30-34% and 35-40% for covering chocolate by Lees and Jackson, Sugar Confectionery and Chocolate Manufacture, Chemical Publishing Co., Inc., New York (1975) pg. 124.
When the fat content of chocolate is reduced, other parameters must be affected in order to maintain the proper rheological properties of the chocolate. The presence of fat in chocolate is important in that the fat covers the surface of all the solid particles. Uncoated surfaces would cause rubbing between the particles and reduce the flow.
Chocolates contain a very large amount of small sugar particles. Fat does not cover the surface of the sugar particles very easily and consequently, anything which will form an interface between the sugar and fat will aid in the flow of the chocolate. Surfactants, e.g., emulsifiers, can produce such an interface by coating the surface of the solid particles, in particular, the sugar. As used herein, the term "surfactant" means any compound that reduces surface tension between a liquid and a solid in solution.
Emulsifiers or surfactants such as lecithin are extremely effective in improving the flow properties of chocolate, and are widely used for their commercial benefit as a partial cocoa butter replacer. It has been reported that the addition of 0.1-0.3% soya lecithin reduces the viscosity by more than 10 times its own weight of cocoa butter. Numerous other emulsifiers have been found to have similar effects as lecithin in lowering the yield value and plastic viscosity. Emulsifier use has generally been limited to less than 1% of the chocolate formulation due to problems such as off-flavors, legal controls, or negative rheological effects at high levels. Since full-fat chocolates at 29-33% total fat typically contain 0.1-0.5% soya lecithin, significantly lower fat levels cannot be achieved by altering the type/level of emulsifier.
Particle size of ingredients is also known to influence the viscosity of chocolate. As the particle size decreases, the viscosity increases as a general rule. An excess of fine particles below 5 microns whether derived from the sugar, milk, or chocolate liquor/powder component, will make the chocolate extremely thick and difficult to manage during pumping, depositing, and enrobing operations. Coarse particles will tend, however, to give the chocolate a gritty sandy texture which is unacceptable to consumers should the particle size exceed 60 microns.
Additionally, it is also well known within the chocolate industry that moisture content has a significant effect on the flow properties of chocolate. If water is added to chocolate, a marked increase in viscosity occurs. It has been previously reported that both the yield value and plastic viscosity increase with moisture levels above 1.1%. Between 0.6-1.1% moisture, the plastic viscosity is nearly constant whereas the yield value rises with increasing moisture. This could be explained by the formation of layers of syrup on the surface of sugar particles with an increase in moisture, which increases the friction between the said particles.
In order to produce a reduced fat chocolate with acceptable flow properties, it is essential to keep the moisture content low. Conching for extended periods of time (longer than 4 hrs.) at elevated temperatures (above 100.degree. F.) is well known to be an effective method for removing water from chocolate paste. The initial ingredients should be selected to have low moisture, and chocolate processing should be done so that moisture uptake from the atmosphere by hygroscopic ingredients is kept to a minimum.
A review of 37 different branded chocolates made by chocolate manufacturers in Europe, Asia or the Americas indicates a range of fat for predominantly milk chocolate from 27.5% to 45.1% by weight fat with an average fat content of 32.7% by weight. Additionally, three branded nonstandardized chocolates manufactured either in Europe or the U.S. were observed with 25.4-26.0% fat. Four branded European dietary chocolates, whereby a sugar alcohol such as mannitol or sorbitol substituted for a nutritive carbohydrate such as sucrose, were by analysis observed to contain from 37.9% to 45.0% fat. Further, analysis of the coating chocolate used in the first 25% less calorie composite bar marketed in the U.S. revealed a coating with 28% fat content. However, to date, despite efforts in the industry, no one has been able to produce a chocolate consisting of less than 25% total fat having flow properties suitable for moulding, extruding or enrobing operations.